Current imaging methods for breast cancer detection and diagnosis are imperfect, especially in high-risk groups composed of younger women with dense breasts. This application for a phased innovation award (R21/R33) proposes novel technology integration centered on magnetic resonance (MR) in combination with microwave methods to produce two new concepts termed Magnetic Resonance Microwave Absorption (MRMA) imaging and Magnetic Resonance-compatible Microwave Tomography (MRMT) initially targeted at imaging breast disease. MRMA exploits MR to measure a thermoelastic wave response induced by local microwave power absorption whereas MRMT utilizes MR to generate coregistered geometrical/anatomical information as priors for image reconstruction in microwave tomography (MT). Depending on certain outcomes from the R21 feasibility studies, a single MRMA + MRMT imaging platform is anticipated, although exit strategies exist for developing MRMA and MRMT in parallel but as separate systems, or for only one or the other of the techniques, alone. Feasibility includes demonstration of (1) MR detection of certain spectral components of the microwave-induced thermoelastic response, (2) electromagnetic compatibility of the heating and sensing subsystems which comprise the composite imaging technique, and (3) physical layout of subsystem elements that would be accommodated in the limited space available for breast imaging within the bore of a standard clinical magnet. The R33 stage of investigation focuses on implementation of data acquisition hardware, image reconstruction software, phantom testing and initial clinical exams using the imaging concepts which prove feasible with the end-goal of realizing a single integration of the MRMA and MRMT principles. If successful, this work offers the potential to lead to novel imaging strategies for breast cancer detection and diagnosis in high-risk groups of women.